No. They aren't.

No. They aren't.

I am we / you / they are he / she/ it is "it" is not plural so you can't use it for "treeS'

Are must also be responded by Are that describes plurality, thus Q: What are these ? A: These are trees. However, since this question below is not about plurality, thus Q: Are you James Bond ? cannotbe responded using : Yes, I are James Bond should be: A: Yes I am James Bond (literally : I IS James Bond)